[PATCH v3] i2c: busses: fix parameter check in i2c_gpio_fault_injector_init()

[PATCH v3] i2c: busses: fix parameter check in i2c_gpio_fault_injector_init()

[Minjie Du]

Make IS_ERR() judge the debugfs_create_dir() function return.
Fixes: 14911c6f48ec ("i2c: gpio: add fault injector")
Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: <stable@vger.kernel.org> # v4.16+

Signed-off-by: Minjie Du <duminjie@vivo.com>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
---
v1-v2:
Fix judge typo.
---
 drivers/i2c/busses/i2c-gpio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
index e5a5b9e8b..545927b96 100644
--- a/drivers/i2c/busses/i2c-gpio.c
+++ b/drivers/i2c/busses/i2c-gpio.c
@@ -265,7 +265,7 @@ static void i2c_gpio_fault_injector_init(struct platform_device *pdev)
 	 */
 	if (!i2c_gpio_debug_dir) {
 		i2c_gpio_debug_dir = debugfs_create_dir("i2c-fault-injector", NULL);
-		if (!i2c_gpio_debug_dir)
+		if (IS_ERR(i2c_gpio_debug_dir))
 			return;
 	}
 
-- 
2.39.0

Re: [PATCH v3] i2c: busses: fix parameter check in i2c_gpio_fault_injector_init()

[Andi Shyti]

Hi Minje,

as Markus suggested, the title

“i2c: gpio: Fix an error check in i2c_gpio_fault_injector_init()”

looks more appropriate and...

On Thu, Jul 13, 2023 at 10:05:17AM +0800, Minjie Du wrote:
> Make IS_ERR() judge the debugfs_create_dir() function return.

... I think you should fix a bit the log here (also Mark has
suggested it). How about something like:

debugfs_create_dir() function returns an error value embedded in
the pointer (PTR_ERR). We need to evaluate the return value using
IS_ERR, rather than checking for NULL.

> Fixes: 14911c6f48ec ("i2c: gpio: add fault injector")
> Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
> Cc: <stable@vger.kernel.org> # v4.16+
> 

don't leave space between tags.

> Signed-off-by: Minjie Du <duminjie@vivo.com>
> Reviewed-by: Andi Shyti <andi.shyti@kernel.org>

At the end it can be something like:

   i2c: gpio: Fix an error check in i2c_gpio_fault_injector_init()
   
   debugfs_create_dir() function returns an error value embedded in 
   the pointer (PTR_ERR). Evaluate the return value using IS_ERR
   rather than checking for NULL.
   
   Fixes: 14911c6f48ec ("i2c: gpio: add fault injector")          
   Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
   Cc: <stable@vger.kernel.org> # v4.16+
   Signed-off-by: Minjie Du <duminjie@vivo.com>
   Reviewed-by: Andi Shyti <andi.shyti@kernel.org>

I'm not sure whether Wolfram can fix it or, if you don't feel
lazy, you can send a v4.

> ---
> v1-v2:
> Fix judge typo.

Please update also the changelog, v2-v3 and v3-v4.

Thanks, Markus, for the suggestions.

Andi

> ---
>  drivers/i2c/busses/i2c-gpio.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
> index e5a5b9e8b..545927b96 100644
> --- a/drivers/i2c/busses/i2c-gpio.c
> +++ b/drivers/i2c/busses/i2c-gpio.c
> @@ -265,7 +265,7 @@ static void i2c_gpio_fault_injector_init(struct platform_device *pdev)
>  	 */
>  	if (!i2c_gpio_debug_dir) {
>  		i2c_gpio_debug_dir = debugfs_create_dir("i2c-fault-injector", NULL);
> -		if (!i2c_gpio_debug_dir)
> +		if (IS_ERR(i2c_gpio_debug_dir))
>  			return;
>  	}
>  
> -- 
> 2.39.0
> 

Re: [PATCH v3] i2c: busses: fix parameter check in i2c_gpio_fault_injector_init()

[Andi Shyti]

Hi Markus,

> > +++ b/drivers/i2c/busses/i2c-gpio.c
> > @@ -265,7 +265,7 @@ static void i2c_gpio_fault_injector_init(struct platform_device *pdev)
> >  	 */
> >  	if (!i2c_gpio_debug_dir) {
> >  		i2c_gpio_debug_dir = debugfs_create_dir("i2c-fault-injector", NULL);
> > -		if (!i2c_gpio_debug_dir)
> > +		if (IS_ERR(i2c_gpio_debug_dir))
> >  			return;
> >  	}
> 
> Will the development attention grow also for the exception handling
> which is missing here so far?

Well, it depends why you need to handle the error return. I think
it's not important if this fails... the only reason I would
handle the error here is to print a warning in dmesg.

Thank you,
Andi