2023-05-22 03:13:03

by Sherry Sun

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 <[email protected]>
---
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

2023-05-22 14:58:14

by Shenwei Wang

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

> -----Original Message-----
> From: Sherry Sun <[email protected]>
> Sent: Sunday, May 21, 2023 9:51 PM
> To: [email protected]; [email protected]; Shenwei Wang
> <[email protected]>; [email protected]
> Cc: [email protected]; [email protected]; dl-linux-imx
> <[email protected]>
> 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 <[email protected]>
> ---
> 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

2023-05-22 16:32:04

by Greg Kroah-Hartman

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

On Mon, May 22, 2023 at 02:45:12PM +0000, Shenwei Wang wrote:
>
>
> > -----Original Message-----
> > From: Sherry Sun <[email protected]>
> > Sent: Sunday, May 21, 2023 9:51 PM
> > To: [email protected]; [email protected]; Shenwei Wang
> > <[email protected]>; [email protected]
> > Cc: [email protected]; [email protected]; dl-linux-imx
> > <[email protected]>
> > 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 <[email protected]>
> > ---
> > 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