[PATCH] dsa: mv88e6xxx: Fix error handling in mv88e6xxx_set_port_state

[PATCH] dsa: mv88e6xxx: Fix error handling in mv88e6xxx_set_port_state

[Guenter Roeck]

Return correct error code if _mv88e6xxx_reg_read returns an error.

Fixes: facd95b2e0ec0 ("net: dsa: mv88e6xxx: Add Hardware bridging support")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 drivers/net/dsa/mv88e6xxx.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/dsa/mv88e6xxx.c b/drivers/net/dsa/mv88e6xxx.c
index fc8d3b6ffe8e..f64186a5f634 100644
--- a/drivers/net/dsa/mv88e6xxx.c
+++ b/drivers/net/dsa/mv88e6xxx.c
@@ -908,8 +908,10 @@ static int mv88e6xxx_set_port_state(struct dsa_switch *ds, int port, u8 state)
 	mutex_lock(&ps->smi_mutex);
 
 	reg = _mv88e6xxx_reg_read(ds, REG_PORT(port), PORT_CONTROL);
-	if (reg < 0)
+	if (reg < 0) {
+		ret = reg;
 		goto abort;
+	}
 
 	oldstate = reg & PORT_CONTROL_STATE_MASK;
 	if (oldstate != state) {
-- 
2.1.0

Re: [PATCH] dsa: mv88e6xxx: Fix error handling in mv88e6xxx_set_port_state

[Andrew Lunn]

On Wed, Apr 15, 2015 at 10:12:42PM -0700, Guenter Roeck wrote:
> Return correct error code if _mv88e6xxx_reg_read returns an error.
> 
> Fixes: facd95b2e0ec0 ("net: dsa: mv88e6xxx: Add Hardware bridging support")
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Hi Guenter

Good catch. I'm surprised there is no compiler warning, possibly used
before set.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

Thanks
	Andrew

> ---
>  drivers/net/dsa/mv88e6xxx.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/dsa/mv88e6xxx.c b/drivers/net/dsa/mv88e6xxx.c
> index fc8d3b6ffe8e..f64186a5f634 100644
> --- a/drivers/net/dsa/mv88e6xxx.c
> +++ b/drivers/net/dsa/mv88e6xxx.c
> @@ -908,8 +908,10 @@ static int mv88e6xxx_set_port_state(struct dsa_switch *ds, int port, u8 state)
>  	mutex_lock(&ps->smi_mutex);
>  
>  	reg = _mv88e6xxx_reg_read(ds, REG_PORT(port), PORT_CONTROL);
> -	if (reg < 0)
> +	if (reg < 0) {
> +		ret = reg;
>  		goto abort;
> +	}
>  
>  	oldstate = reg & PORT_CONTROL_STATE_MASK;
>  	if (oldstate != state) {
> -- 
> 2.1.0
> 
> --
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Re: [PATCH] dsa: mv88e6xxx: Fix error handling in mv88e6xxx_set_port_state

[Guenter Roeck]

On 04/16/2015 05:37 AM, Andrew Lunn wrote:
> On Wed, Apr 15, 2015 at 10:12:42PM -0700, Guenter Roeck wrote:
>> Return correct error code if _mv88e6xxx_reg_read returns an error.
>>
>> Fixes: facd95b2e0ec0 ("net: dsa: mv88e6xxx: Add Hardware bridging support")
>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>
> Hi Guenter
>
> Good catch. I'm surprised there is no compiler warning, possibly used
> before set.
>
There was, actually. No idea how I missed that. Fengguang's build bots caught it.

> Reviewed-by: Andrew Lunn <andrew@lunn.ch>
>
Thanks!

Guenter

Re: [PATCH] dsa: mv88e6xxx: Fix error handling in mv88e6xxx_set_port_state

[Guenter Roeck]

On 04/15/2015 10:12 PM, Guenter Roeck wrote:
> Return correct error code if _mv88e6xxx_reg_read returns an error.
>
> Fixes: facd95b2e0ec0 ("net: dsa: mv88e6xxx: Add Hardware bridging support")
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

I should have given proper credit.

Reported-by: kbuild test robot <fengguang.wu@intel.com>

For the curious, neither W=1, W=2, C-1, C=2, nor sparse report this problem,
at least not with gcc 4.9.1.

Guenter

Re: [PATCH] dsa: mv88e6xxx: Fix error handling in mv88e6xxx_set_port_state

[Geert Uytterhoeven]

On Thu, Apr 16, 2015 at 3:46 PM, Guenter Roeck <linux@roeck-us.net> wrote:
> On 04/15/2015 10:12 PM, Guenter Roeck wrote:
>>
>> Return correct error code if _mv88e6xxx_reg_read returns an error.
>>
>> Fixes: facd95b2e0ec0 ("net: dsa: mv88e6xxx: Add Hardware bridging
>> support")
>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>
>
> I should have given proper credit.
>
> Reported-by: kbuild test robot <fengguang.wu@intel.com>
>
> For the curious, neither W=1, W=2, C-1, C=2, nor sparse report this problem,
> at least not with gcc 4.9.1.

Good old gcc 4.1.2 (which I still use for m68k builds, and won't retire anytime
soon as it finds real bugs in every new kernel release) says:

    drivers/net/dsa/mv88e6xxx.c: In function ‘mv88e6xxx_set_port_state’:
    drivers/net/dsa/mv88e6xxx.c:905: warning: ‘ret’ may be used
uninitialized in this function

Even after your patch, as it missed one case (patch sent).

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH] dsa: mv88e6xxx: Fix error handling in mv88e6xxx_set_port_state

[Guenter Roeck]

On 04/16/2015 11:51 AM, Geert Uytterhoeven wrote:
> On Thu, Apr 16, 2015 at 3:46 PM, Guenter Roeck <linux@roeck-us.net> wrote:
>> On 04/15/2015 10:12 PM, Guenter Roeck wrote:
>>>
>>> Return correct error code if _mv88e6xxx_reg_read returns an error.
>>>
>>> Fixes: facd95b2e0ec0 ("net: dsa: mv88e6xxx: Add Hardware bridging
>>> support")
>>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>>
>>
>> I should have given proper credit.
>>
>> Reported-by: kbuild test robot <fengguang.wu@intel.com>
>>
>> For the curious, neither W=1, W=2, C-1, C=2, nor sparse report this problem,
>> at least not with gcc 4.9.1.
>
> Good old gcc 4.1.2 (which I still use for m68k builds, and won't retire anytime
> soon as it finds real bugs in every new kernel release) says:
>
>      drivers/net/dsa/mv88e6xxx.c: In function ‘mv88e6xxx_set_port_state’:
>      drivers/net/dsa/mv88e6xxx.c:905: warning: ‘ret’ may be used
> uninitialized in this function
>
> Even after your patch, as it missed one case (patch sent).
>

Grumble. So much for trusting tools :-(

Thanks for fixing this!

Guenter

Re: [PATCH] dsa: mv88e6xxx: Fix error handling in mv88e6xxx_set_port_state

[David Miller]

From: Guenter Roeck <linux@roeck-us.net>
Date: Wed, 15 Apr 2015 22:12:42 -0700

> Return correct error code if _mv88e6xxx_reg_read returns an error.
> 
> Fixes: facd95b2e0ec0 ("net: dsa: mv88e6xxx: Add Hardware bridging support")
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Applied, thanks.