[PATCH 1/1] net: bcmgenet: fix incorrect return value checks

[PATCH 1/1] net: bcmgenet: fix incorrect return value checks

[Pan Bian]

From: Pan Bian <bianpan2016@163.com>

Function platform_get_irq() will return a negative value on errors.
However, in function bcmgenet_probe(), 0 is considered as a flag of
error. This patch fixes the bug by checking whether the return value of
platform_get_irq() is less than 0.

Signed-off-by: Pan Bian <bianpan2016@163.com>
---
 drivers/net/ethernet/broadcom/genet/bcmgenet.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
index 365895e..0bccf2b 100644
--- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
@@ -3329,7 +3329,7 @@ static int bcmgenet_probe(struct platform_device *pdev)
 	priv->irq0 = platform_get_irq(pdev, 0);
 	priv->irq1 = platform_get_irq(pdev, 1);
 	priv->wol_irq = platform_get_irq(pdev, 2);
-	if (!priv->irq0 || !priv->irq1) {
+	if (priv->irq0 < 0 || priv->irq1 < 0) {
 		dev_err(&pdev->dev, "can't find IRQs\n");
 		err = -EINVAL;
 		goto err;
-- 
1.9.1

Re: [PATCH 1/1] net: bcmgenet: fix incorrect return value checks

[David Miller]

From: Pan Bian <bianpan201602@163.com>
Date: Sun, 23 Apr 2017 18:01:05 +0800

> From: Pan Bian <bianpan2016@163.com>
> 
> Function platform_get_irq() will return a negative value on errors.
> However, in function bcmgenet_probe(), 0 is considered as a flag of
> error. This patch fixes the bug by checking whether the return value of
> platform_get_irq() is less than 0.
> 
> Signed-off-by: Pan Bian <bianpan2016@163.com>

I'm definitely not confident enough to apply this.

On some platform zero IRQs are invalid.

There are also lots of pieces of code that check the return value ">
0" as success.

Re: [PATCH 1/1] net: bcmgenet: fix incorrect return value checks

[Florian Fainelli]

On 04/24/2017 12:48 PM, David Miller wrote:
> From: Pan Bian <bianpan201602@163.com>
> Date: Sun, 23 Apr 2017 18:01:05 +0800
> 
>> From: Pan Bian <bianpan2016@163.com>
>>
>> Function platform_get_irq() will return a negative value on errors.
>> However, in function bcmgenet_probe(), 0 is considered as a flag of
>> error. This patch fixes the bug by checking whether the return value of
>> platform_get_irq() is less than 0.
>>
>> Signed-off-by: Pan Bian <bianpan2016@163.com>
> 
> I'm definitely not confident enough to apply this.
> 
> On some platform zero IRQs are invalid.
> 
> There are also lots of pieces of code that check the return value ">
> 0" as success.
> 

I don't think we are fixing any real issue by applying this patch, but I
will do a check on ARM, ARM64 and MIPS where this driver is used to see
if it is even remotely possible to have a 0 IRQ.
-- 
Florian