diff mbox series

[1/6] USB: serial: cp210x: fix control-characters error handling

Message ID 20210702134227.24621-2-johan@kernel.org (mailing list archive)
State Superseded
Headers show
Series USB: serial: cp210x: fixes and CP2105/CP2108 fw version | expand

Commit Message

Johan Hovold July 2, 2021, 1:42 p.m. UTC
In the unlikely event that setting the software flow-control characters
fails the other flow-control settings should still be updated.

Fixes: 7748feffcd80 ("USB: serial: cp210x: add support for software flow control")
Cc: stable@vger.kernel.org	# 5.11
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/cp210x.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

Comments

Greg KH July 2, 2021, 2:47 p.m. UTC | #1
On Fri, Jul 02, 2021 at 03:42:22PM +0200, Johan Hovold wrote:
> In the unlikely event that setting the software flow-control characters
> fails the other flow-control settings should still be updated.
> 
> Fixes: 7748feffcd80 ("USB: serial: cp210x: add support for software flow control")
> Cc: stable@vger.kernel.org	# 5.11
> Signed-off-by: Johan Hovold <johan@kernel.org>
> ---
>  drivers/usb/serial/cp210x.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
> index 09b845d0da41..b41e2c7649fb 100644
> --- a/drivers/usb/serial/cp210x.c
> +++ b/drivers/usb/serial/cp210x.c
> @@ -1217,9 +1217,7 @@ static void cp210x_set_flow_control(struct tty_struct *tty,
>  		chars.bXonChar = START_CHAR(tty);
>  		chars.bXoffChar = STOP_CHAR(tty);
>  
> -		ret = cp210x_set_chars(port, &chars);
> -		if (ret)
> -			return;
> +		cp210x_set_chars(port, &chars);

What's the odds that someone tries to add the error checking back in
here, in a few years?  Can you put a comment here saying why you are not
checking it?

thanks,

greg k-h
Johan Hovold July 5, 2021, 7:40 a.m. UTC | #2
On Fri, Jul 02, 2021 at 04:47:11PM +0200, Greg Kroah-Hartman wrote:
> On Fri, Jul 02, 2021 at 03:42:22PM +0200, Johan Hovold wrote:
> > In the unlikely event that setting the software flow-control characters
> > fails the other flow-control settings should still be updated.
> > 
> > Fixes: 7748feffcd80 ("USB: serial: cp210x: add support for software flow control")
> > Cc: stable@vger.kernel.org	# 5.11
> > Signed-off-by: Johan Hovold <johan@kernel.org>
> > ---
> >  drivers/usb/serial/cp210x.c | 4 +---
> >  1 file changed, 1 insertion(+), 3 deletions(-)
> > 
> > diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
> > index 09b845d0da41..b41e2c7649fb 100644
> > --- a/drivers/usb/serial/cp210x.c
> > +++ b/drivers/usb/serial/cp210x.c
> > @@ -1217,9 +1217,7 @@ static void cp210x_set_flow_control(struct tty_struct *tty,
> >  		chars.bXonChar = START_CHAR(tty);
> >  		chars.bXoffChar = STOP_CHAR(tty);
> >  
> > -		ret = cp210x_set_chars(port, &chars);
> > -		if (ret)
> > -			return;
> > +		cp210x_set_chars(port, &chars);
> 
> What's the odds that someone tries to add the error checking back in
> here, in a few years?  Can you put a comment here saying why you are not
> checking it?

This is just how set_termios() works and how the other requests are
handled by the driver. I can add an explicit error message here though
just like when setting the line-control register so that it doesn't look
like an oversight. The error message is currently printed by the
set_chars() helper, but I can move that out when removing the helper
later in the series.

Johan
diff mbox series

Patch

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index 09b845d0da41..b41e2c7649fb 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -1217,9 +1217,7 @@  static void cp210x_set_flow_control(struct tty_struct *tty,
 		chars.bXonChar = START_CHAR(tty);
 		chars.bXoffChar = STOP_CHAR(tty);
 
-		ret = cp210x_set_chars(port, &chars);
-		if (ret)
-			return;
+		cp210x_set_chars(port, &chars);
 	}
 
 	mutex_lock(&port_priv->mutex);