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 <[email protected]> Signed-off-by: Vipul Kumar <[email protected]> Signed-off-by: Sherry Sun <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
chewitt · Aug 18, 2021 · 88c1d24 · 88c1d24
1 parent 1143637
commit 88c1d24
Showing 1 changed file with 4 additions and 0 deletions.
diff --git 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);