[PATCH] tty: serial: fsl_lpuart: Check the return value of dmaengine_tx_status

[PATCH] tty: serial: fsl_lpuart: Check the return value of dmaengine_tx_status

[Sherry Sun]

Coverity reports the Unchecked return value (CHECKED_RETURN) warning:
Calling dmaengine_tx_status without checking return value.

So here add the return value check for dmaengine_tx_status() function to
make coverity happy.

Fixes: cf9aa72d2f91 ("tty: serial: fsl_lpuart: optimize the timer based EOP logic")
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
---
 drivers/tty/serial/fsl_lpuart.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 92a3bd0f4158..f2a47a8c5b85 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -1286,13 +1286,19 @@ static void lpuart_dma_rx_complete(void *arg)
 static void lpuart_timer_func(struct timer_list *t)
 {
 	struct lpuart_port *sport = from_timer(sport, t, lpuart_timer);
+	enum dma_status dmastat;
 	struct dma_chan *chan = sport->dma_rx_chan;
 	struct circ_buf *ring = &sport->rx_ring;
 	struct dma_tx_state state;
 	unsigned long flags;
 	int count;
 
-	dmaengine_tx_status(chan, sport->dma_rx_cookie, &state);
+	dmastat = dmaengine_tx_status(chan, sport->dma_rx_cookie, &state);
+	if (dmastat == DMA_ERROR) {
+		dev_err(sport->port.dev, "Rx DMA transfer failed!\n");
+		return;
+	}
+
 	ring->head = sport->rx_sgl.length - state.residue;
 	count = CIRC_CNT(ring->head, ring->tail, sport->rx_sgl.length);
 
-- 
2.17.1

RE: [PATCH] tty: serial: fsl_lpuart: Check the return value of dmaengine_tx_status

[Shenwei Wang]

> -----Original Message-----
> From: Sherry Sun <sherry.sun@nxp.com>
> Sent: Sunday, May 21, 2023 9:51 PM
> To: gregkh@linuxfoundation.org; jirislaby@kernel.org; Shenwei Wang
> <shenwei.wang@nxp.com>; ilpo.jarvinen@linux.intel.com
> Cc: linux-serial@vger.kernel.org; linux-kernel@vger.kernel.org; dl-linux-imx
> <linux-imx@nxp.com>
> Subject: [PATCH] tty: serial: fsl_lpuart: Check the return value of
> dmaengine_tx_status
> 
> Coverity reports the Unchecked return value (CHECKED_RETURN) warning:
> Calling dmaengine_tx_status without checking return value.
> 
> So here add the return value check for dmaengine_tx_status() function to make
> coverity happy.
> 
> Fixes: cf9aa72d2f91 ("tty: serial: fsl_lpuart: optimize the timer based EOP logic")
> Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
> ---
>  drivers/tty/serial/fsl_lpuart.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index
> 92a3bd0f4158..f2a47a8c5b85 100644
> --- a/drivers/tty/serial/fsl_lpuart.c
> +++ b/drivers/tty/serial/fsl_lpuart.c
> @@ -1286,13 +1286,19 @@ static void lpuart_dma_rx_complete(void *arg)
> static void lpuart_timer_func(struct timer_list *t)  {
>  	struct lpuart_port *sport = from_timer(sport, t, lpuart_timer);
> +	enum dma_status dmastat;

Should be reverse Christmas tree order.

Regards,
Shenwei

>  	struct dma_chan *chan = sport->dma_rx_chan;
>  	struct circ_buf *ring = &sport->rx_ring;
>  	struct dma_tx_state state;
>  	unsigned long flags;
>  	int count;
> 
> -	dmaengine_tx_status(chan, sport->dma_rx_cookie, &state);
> +	dmastat = dmaengine_tx_status(chan, sport->dma_rx_cookie, &state);
> +	if (dmastat == DMA_ERROR) {
> +		dev_err(sport->port.dev, "Rx DMA transfer failed!\n");
> +		return;
> +	}
> +
>  	ring->head = sport->rx_sgl.length - state.residue;
>  	count = CIRC_CNT(ring->head, ring->tail, sport->rx_sgl.length);
> 
> --
> 2.17.1

Re: [PATCH] tty: serial: fsl_lpuart: Check the return value of dmaengine_tx_status

[gregkh]

On Mon, May 22, 2023 at 02:45:12PM +0000, Shenwei Wang wrote:
> 
> 
> > -----Original Message-----
> > From: Sherry Sun <sherry.sun@nxp.com>
> > Sent: Sunday, May 21, 2023 9:51 PM
> > To: gregkh@linuxfoundation.org; jirislaby@kernel.org; Shenwei Wang
> > <shenwei.wang@nxp.com>; ilpo.jarvinen@linux.intel.com
> > Cc: linux-serial@vger.kernel.org; linux-kernel@vger.kernel.org; dl-linux-imx
> > <linux-imx@nxp.com>
> > Subject: [PATCH] tty: serial: fsl_lpuart: Check the return value of
> > dmaengine_tx_status
> > 
> > Coverity reports the Unchecked return value (CHECKED_RETURN) warning:
> > Calling dmaengine_tx_status without checking return value.
> > 
> > So here add the return value check for dmaengine_tx_status() function to make
> > coverity happy.
> > 
> > Fixes: cf9aa72d2f91 ("tty: serial: fsl_lpuart: optimize the timer based EOP logic")
> > Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
> > ---
> >  drivers/tty/serial/fsl_lpuart.c | 8 +++++++-
> >  1 file changed, 7 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index
> > 92a3bd0f4158..f2a47a8c5b85 100644
> > --- a/drivers/tty/serial/fsl_lpuart.c
> > +++ b/drivers/tty/serial/fsl_lpuart.c
> > @@ -1286,13 +1286,19 @@ static void lpuart_dma_rx_complete(void *arg)
> > static void lpuart_timer_func(struct timer_list *t)  {
> >  	struct lpuart_port *sport = from_timer(sport, t, lpuart_timer);
> > +	enum dma_status dmastat;
> 
> Should be reverse Christmas tree order.

Not a requirement at all, please don't force it.

thanks,

greg k-h