[PATCH v2] serial: sccnxp: Improve verify_port

[PATCH v2] serial: sccnxp: Improve verify_port

[Alexander Shiyan]

The patch improves verify_port procedure by comparing the type of
port and IRQ numbers simultaneously. This can be important in the
case of multiple drivers SCCNXP in the system that are different IRQs.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
---
 drivers/tty/serial/sccnxp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/sccnxp.c b/drivers/tty/serial/sccnxp.c
index c773041..92e6195 100644
--- a/drivers/tty/serial/sccnxp.c
+++ b/drivers/tty/serial/sccnxp.c
@@ -713,8 +713,8 @@ static void sccnxp_config_port(struct uart_port *port, int flags)
 
 static int sccnxp_verify_port(struct uart_port *port, struct serial_struct *s)
 {
-	if ((s->type == PORT_UNKNOWN) || (s->type == PORT_SC26XX))
-		return 0;
+	if ((s->type != PORT_UNKNOWN) && (s->type != PORT_SC26XX))
+		return -EINVAL;
 	if (s->irq == port->irq)
 		return 0;
 
-- 
1.8.1.5

Re: [PATCH v2] serial: sccnxp: Improve verify_port

[Greg Kroah-Hartman]

On Tue, May 14, 2013 at 07:59:11PM +0400, Alexander Shiyan wrote:
> The patch improves verify_port procedure by comparing the type of
> port and IRQ numbers simultaneously. This can be important in the
> case of multiple drivers SCCNXP in the system that are different IRQs.

So this fixes a bug?  Really?

> Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
> ---
>  drivers/tty/serial/sccnxp.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/sccnxp.c b/drivers/tty/serial/sccnxp.c
> index c773041..92e6195 100644
> --- a/drivers/tty/serial/sccnxp.c
> +++ b/drivers/tty/serial/sccnxp.c
> @@ -713,8 +713,8 @@ static void sccnxp_config_port(struct uart_port *port, int flags)
>  
>  static int sccnxp_verify_port(struct uart_port *port, struct serial_struct *s)
>  {
> -	if ((s->type == PORT_UNKNOWN) || (s->type == PORT_SC26XX))
> -		return 0;
> +	if ((s->type != PORT_UNKNOWN) && (s->type != PORT_SC26XX))
> +		return -EINVAL;

Why are you now returning a different value?

thanks,

greg k-h

Re[2]: [PATCH v2] serial: sccnxp: Improve verify_port

[Alexander Shiyan]

> On Tue, May 14, 2013 at 07:59:11PM +0400, Alexander Shiyan wrote:
> > The patch improves verify_port procedure by comparing the type of
> > port and IRQ numbers simultaneously. This can be important in the
> > case of multiple drivers SCCNXP in the system that are different IRQs.
> 
> So this fixes a bug?  Really?

Only in theory.

> > Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
> > ---
> >  drivers/tty/serial/sccnxp.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/tty/serial/sccnxp.c b/drivers/tty/serial/sccnxp.c
> > index c773041..92e6195 100644
> > --- a/drivers/tty/serial/sccnxp.c
> > +++ b/drivers/tty/serial/sccnxp.c
> > @@ -713,8 +713,8 @@ static void sccnxp_config_port(struct uart_port *port, int flags)
> >  
> >  static int sccnxp_verify_port(struct uart_port *port, struct serial_struct *s)
> >  {
> > -	if ((s->type == PORT_UNKNOWN) || (s->type == PORT_SC26XX))
> > -		return 0;
> > +	if ((s->type != PORT_UNKNOWN) && (s->type != PORT_SC26XX))
> > +		return -EINVAL;
> 
> Why are you now returning a different value?

Value is not different. Patch just change logic a bit. Zero on success,
same as before.

---

Re: [PATCH v2] serial: sccnxp: Improve verify_port

[Greg Kroah-Hartman]

On Tue, May 14, 2013 at 08:30:47PM +0400, Alexander Shiyan wrote:
> > On Tue, May 14, 2013 at 07:59:11PM +0400, Alexander Shiyan wrote:
> > > The patch improves verify_port procedure by comparing the type of
> > > port and IRQ numbers simultaneously. This can be important in the
> > > case of multiple drivers SCCNXP in the system that are different IRQs.
> > 
> > So this fixes a bug?  Really?
> 
> Only in theory.

How?  It really doesn't look like you are doing anything here, except
rearranging the logic to look different, but yet do the same thing.

So again, why are you doing this?

greg k-h

Re[2]: [PATCH v2] serial: sccnxp: Improve verify_port

[Alexander Shiyan]

> > > On Tue, May 14, 2013 at 07:59:11PM +0400, Alexander Shiyan wrote:
> > > > The patch improves verify_port procedure by comparing the type of
> > > > port and IRQ numbers simultaneously. This can be important in the
> > > > case of multiple drivers SCCNXP in the system that are different IRQs.
> > > 
> > > So this fixes a bug?  Really?
> > 
> > Only in theory.
> 
> How?  It really doesn't look like you are doing anything here, except
> rearranging the logic to look different, but yet do the same thing.

Procedure do not compare IRQ before if port type is valid.

> So again, why are you doing this?

Well, just drop this patch. I cannot say more than now.

---