[PATCH v2] platform: don't return 0 from platform_get_irq[_byname]() on error

[PATCH v2] platform: don't return 0 from platform_get_irq[_byname]() on error

[Sergei Shtylyov]

of_irq_get[_byname]() return 0 iff  irq_create_of_mapping() call fails.
Returning both  error code and 0 on failure is a sign of a misdesigned API,
it makes the failure check unnecessarily complex and error prone. We should
rely  on the platform IRQ resource in this case, not return 0,  especially
as 0 can be  a valid  IRQ resource too...

Fixes: aff008ad813c ("platform_get_irq: Revert to platform_get_resource if of_irq_get fails")
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
CC: stable@vger.kernel.org

---
The patch is against the 'driver-core-linus' branch of Greg KH's
'driver-core.git' repo.

See also commit 3993546646ba ("of: irq: fix of_irq_get[_byname]() kernel-doc")

Changes in version 2:
- expanded the changelog.

 drivers/base/platform.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Index: driver-core/drivers/base/platform.c
===================================================================
--- driver-core.orig/drivers/base/platform.c
+++ driver-core/drivers/base/platform.c
@@ -97,7 +97,7 @@ int platform_get_irq(struct platform_dev
 		int ret;
 
 		ret = of_irq_get(dev->dev.of_node, num);
-		if (ret >= 0 || ret == -EPROBE_DEFER)
+		if (ret > 0 || ret == -EPROBE_DEFER)
 			return ret;
 	}
 
@@ -175,7 +175,7 @@ int platform_get_irq_byname(struct platf
 		int ret;
 
 		ret = of_irq_get_byname(dev->dev.of_node, name);
-		if (ret >= 0 || ret == -EPROBE_DEFER)
+		if (ret > 0 || ret == -EPROBE_DEFER)
 			return ret;
 	}
 

Re: [PATCH v2] platform: don't return 0 from platform_get_irq[_byname]() on error

[Sergei Shtylyov]

Hello.

On 7/4/2016 1:04 AM, Sergei Shtylyov wrote:

> of_irq_get[_byname]() return 0 iff  irq_create_of_mapping() call fails.
> Returning both  error code and 0 on failure is a sign of a misdesigned API,
> it makes the failure check unnecessarily complex and error prone. We should
> rely  on the platform IRQ resource in this case, not return 0,  especially
> as 0 can be  a valid  IRQ resource too...
>
> Fixes: aff008ad813c ("platform_get_irq: Revert to platform_get_resource if of_irq_get fails")
> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
> CC: stable@vger.kernel.org

    4.7 has been tagged now. Can I count on this patch getting to 4.8? Or at 
least some feedback given? :-/

> ---
> The patch is against the 'driver-core-linus' branch of Greg KH's
> 'driver-core.git' repo.
>
> See also commit 3993546646ba ("of: irq: fix of_irq_get[_byname]() kernel-doc")
>
> Changes in version 2:
> - expanded the changelog.
>
>  drivers/base/platform.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> Index: driver-core/drivers/base/platform.c
> ===================================================================
> --- driver-core.orig/drivers/base/platform.c
> +++ driver-core/drivers/base/platform.c
> @@ -97,7 +97,7 @@ int platform_get_irq(struct platform_dev
>  		int ret;
>
>  		ret = of_irq_get(dev->dev.of_node, num);
> -		if (ret >= 0 || ret == -EPROBE_DEFER)
> +		if (ret > 0 || ret == -EPROBE_DEFER)
>  			return ret;
>  	}
>
> @@ -175,7 +175,7 @@ int platform_get_irq_byname(struct platf
>  		int ret;
>
>  		ret = of_irq_get_byname(dev->dev.of_node, name);
> -		if (ret >= 0 || ret == -EPROBE_DEFER)
> +		if (ret > 0 || ret == -EPROBE_DEFER)
>  			return ret;
>  	}
>

MBR, Sergei

Re: [PATCH v2] platform: don't return 0 from platform_get_irq[_byname]() on error

[Greg Kroah-Hartman]

On Mon, Jul 25, 2016 at 02:55:37PM +0300, Sergei Shtylyov wrote:
> Hello.
> 
> On 7/4/2016 1:04 AM, Sergei Shtylyov wrote:
> 
> > of_irq_get[_byname]() return 0 iff  irq_create_of_mapping() call fails.
> > Returning both  error code and 0 on failure is a sign of a misdesigned API,
> > it makes the failure check unnecessarily complex and error prone. We should
> > rely  on the platform IRQ resource in this case, not return 0,  especially
> > as 0 can be  a valid  IRQ resource too...
> > 
> > Fixes: aff008ad813c ("platform_get_irq: Revert to platform_get_resource if of_irq_get fails")
> > Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
> > CC: stable@vger.kernel.org
> 
>    4.7 has been tagged now. Can I count on this patch getting to 4.8? Or at
> least some feedback given? :-/

I'll get to it after 4.8-rc1 is out, but ideally one of the of
developers would look at it, as I have no way to test this...

thanks,

greg k-h