From: Fugang Duan <fugang.duan@nxp.com>
Date: Tue, 17 Aug 2021 10:02:03 +0000 (+0800)
Subject: tty: serial: fsl_lpuart: check dma_tx_in_progress in tx dma callback
X-Git-Tag: v5.15-rc1~153^2~12
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=88c1d2478ec8a420cf60a3c25503e37b34fea5aa;p=thirdparty%2Flinux.git

tty: serial: fsl_lpuart: check dma_tx_in_progress in tx dma callback

There have a corner case that tx DMA .callback() is coming after
.flush_buffer(), then .callback() should check dma_tx_in_progress
flag and return in directly.

Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Vipul Kumar <vipul_kumar@mentor.com>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20210817100203.21300-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index f0e5da77ed6d4..31d715c4787a3 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -479,6 +479,10 @@ static void lpuart_dma_tx_complete(void *arg)
 	unsigned long flags;
 
 	spin_lock_irqsave(&sport->port.lock, flags);
+	if (!sport->dma_tx_in_progress) {
+		spin_unlock_irqrestore(&sport->port.lock, flags);
+		return;
+	}
 
 	dma_unmap_sg(chan->device->dev, sgl, sport->dma_tx_nents,
 		     DMA_TO_DEVICE);