tty: serial: fsl_lpuart: make coverity happy

Coverity reports the following:

  var_compare_op: Comparing chan to null implies that chan might be null.

  1234        if (chan)
  1235                dmaengine_terminate_all(chan);
  1236

  Dereference after null check (FORWARD_NULL)
  var_deref_op: Dereferencing null pointer chan.

  1237        dma_unmap_sg(chan->device->dev, &sport->rx_sgl, 1, DMA_FROM_DEVICE);

Technically, this is correct. But lpuart_dma_rx_free() is guarded by
lpuart_dma_rx_use which is only true if there is a dma channel, see
lpuart_rx_dma_startup(). In any way, this looks bogus. So remove
the superfluous "if (chan)" check and make coverity happy.

Fixes: a092ab25fdaa ("tty: serial: fsl_lpuart: fix DMA mapping")
Signed-off-by: Michael Walle <michael@walle.cc>
Reported-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Jiri Slaby <jslaby@suse.cz>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Link: https://lore.kernel.org/r/20200403174942.9594-1-michael@walle.cc
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 5d41075..dba730d 100644 (file)
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -1231,9 +1231,7 @@ static void lpuart_dma_rx_free(struct uart_port *port)
                                        struct lpuart_port, port);
        struct dma_chan *chan = sport->dma_rx_chan;
 
-       if (chan)
-               dmaengine_terminate_all(chan);
-
+       dmaengine_terminate_all(chan);
        dma_unmap_sg(chan->device->dev, &sport->rx_sgl, 1, DMA_FROM_DEVICE);
        kfree(sport->rx_ring.buf);
        sport->rx_ring.tail = 0;