[PATCH net] net: sunhme: Return an error when we are out of slots

[PATCH net] net: sunhme: Return an error when we are out of slots

[Sean Anderson]

We only allocate enough space for four devices when the parent is a QFE. If
we couldn't find a spot (because five devices were created for whatever
reason), we would not return an error from probe(). Return ENODEV, which
was what we did before.

Fixes: 96c6e9faecf1 ("sunhme: forward the error code from pci_enable_device()")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Sean Anderson <seanga2@gmail.com>
---

 drivers/net/ethernet/sun/sunhme.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/sun/sunhme.c b/drivers/net/ethernet/sun/sunhme.c
index 1c16548415cd..523e26653ec8 100644
--- a/drivers/net/ethernet/sun/sunhme.c
+++ b/drivers/net/ethernet/sun/sunhme.c
@@ -2861,12 +2861,13 @@ static int happy_meal_pci_probe(struct pci_dev *pdev,
 
 		for (qfe_slot = 0; qfe_slot < 4; qfe_slot++)
 			if (!qp->happy_meals[qfe_slot])
-				break;
+				goto found_slot;
 
-		if (qfe_slot == 4)
-			goto err_out;
+		err = -ENODEV;
+		goto err_out;
 	}
 
+found_slot:
 	dev = devm_alloc_etherdev(&pdev->dev, sizeof(struct happy_meal));
 	if (!dev) {
 		err = -ENOMEM;
-- 
2.37.1

Re: [PATCH net] net: sunhme: Return an error when we are out of slots

[Simon Horman]

On Wed, Feb 22, 2023 at 12:09:35PM -0500, Sean Anderson wrote:
> We only allocate enough space for four devices when the parent is a QFE. If
> we couldn't find a spot (because five devices were created for whatever
> reason), we would not return an error from probe(). Return ENODEV, which
> was what we did before.
> 
> Fixes: 96c6e9faecf1 ("sunhme: forward the error code from pci_enable_device()")

I think the hash for that commit is acb3f35f920b.

However, I also think this problem was introduced by the first hunk of
5b3dc6dda6b1 ("sunhme: Regularize probe errors").

Which is:

--- a/drivers/net/ethernet/sun/sunhme.c
+++ b/drivers/net/ethernet/sun/sunhme.c
@@ -2945,7 +2945,6 @@ static int happy_meal_pci_probe(struct pci_dev *pdev,
 	if (err)
 		goto err_out;
 	pci_set_master(pdev);
-	err = -ENODEV;
 
 	if (!strcmp(prom_name, "SUNW,qfe") || !strcmp(prom_name, "qfe")) {
 		qp = quattro_pci_find(pdev);


Which leads me to wonder if simpler fixes would be either:

1) Reverting the hunk above
2) Or, more in keeping with the rest of that patch,
   explicitly setting err before branching to err_out,
   as you your patch does, but without other logic changes.

   Something like this (*compile tested only!*:

diff --git a/drivers/net/ethernet/sun/sunhme.c b/drivers/net/ethernet/sun/sunhme.c
index 1c16548415cd..2409e7d6c29e 100644
--- a/drivers/net/ethernet/sun/sunhme.c
+++ b/drivers/net/ethernet/sun/sunhme.c
@@ -2863,8 +2863,10 @@ static int happy_meal_pci_probe(struct pci_dev *pdev,
 			if (!qp->happy_meals[qfe_slot])
 				break;
 
-		if (qfe_slot == 4)
+		if (qfe_slot == 4) {
+			err = -ENOMEM;
 			goto err_out;
+		}
 	}
 
 	dev = devm_alloc_etherdev(&pdev->dev, sizeof(struct happy_meal));

Also, I am curious why happy_meal_pci_probe() doesn't just return instaed
of branching to err_out. As err_out only returns err.  I guess there is a
reason for it. But simply returning would probably simplify error handling.
(I'm not suggesting that approach for this fix.)

> Reported-by: kernel test robot <lkp@intel.com>
> Reported-by: Dan Carpenter <error27@gmail.com>
> Signed-off-by: Sean Anderson <seanga2@gmail.com>
> ---
> 
>  drivers/net/ethernet/sun/sunhme.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/ethernet/sun/sunhme.c b/drivers/net/ethernet/sun/sunhme.c
> index 1c16548415cd..523e26653ec8 100644
> --- a/drivers/net/ethernet/sun/sunhme.c
> +++ b/drivers/net/ethernet/sun/sunhme.c
> @@ -2861,12 +2861,13 @@ static int happy_meal_pci_probe(struct pci_dev *pdev,
>  
>  		for (qfe_slot = 0; qfe_slot < 4; qfe_slot++)
>  			if (!qp->happy_meals[qfe_slot])
> -				break;
> +				goto found_slot;
>  
> -		if (qfe_slot == 4)
> -			goto err_out;
> +		err = -ENODEV;
> +		goto err_out;
>  	}
>  
> +found_slot:
>  	dev = devm_alloc_etherdev(&pdev->dev, sizeof(struct happy_meal));
>  	if (!dev) {
>  		err = -ENOMEM;
> -- 
> 2.37.1
> 

Re: [PATCH net] net: sunhme: Return an error when we are out of slots

[Sean Anderson]

On 2/22/23 15:59, Simon Horman wrote:
> On Wed, Feb 22, 2023 at 12:09:35PM -0500, Sean Anderson wrote:
>> We only allocate enough space for four devices when the parent is a QFE. If
>> we couldn't find a spot (because five devices were created for whatever
>> reason), we would not return an error from probe(). Return ENODEV, which
>> was what we did before.
>>
>> Fixes: 96c6e9faecf1 ("sunhme: forward the error code from pci_enable_device()")
> 
> I think the hash for that commit is acb3f35f920b.

Ah, sorry that's my local copy. The upstream commit is as you noted.

> 
> However, I also think this problem was introduced by the first hunk of
> 5b3dc6dda6b1 ("sunhme: Regularize probe errors").
> 
> Which is:
> 
> --- a/drivers/net/ethernet/sun/sunhme.c
> +++ b/drivers/net/ethernet/sun/sunhme.c
> @@ -2945,7 +2945,6 @@ static int happy_meal_pci_probe(struct pci_dev *pdev,
>   	if (err)
>   		goto err_out;
>   	pci_set_master(pdev);
> -	err = -ENODEV;
>   
>   	if (!strcmp(prom_name, "SUNW,qfe") || !strcmp(prom_name, "qfe")) {
>   		qp = quattro_pci_find(pdev);
> 

Yes. That's the one I should have blamed.

> Which leads me to wonder if simpler fixes would be either:
> 
> 1) Reverting the hunk above
> 2) Or, more in keeping with the rest of that patch,
>     explicitly setting err before branching to err_out,
>     as you your patch does, but without other logic changes.

>     Something like this (*compile tested only!*:
> 
> diff --git a/drivers/net/ethernet/sun/sunhme.c b/drivers/net/ethernet/sun/sunhme.c
> index 1c16548415cd..2409e7d6c29e 100644
> --- a/drivers/net/ethernet/sun/sunhme.c
> +++ b/drivers/net/ethernet/sun/sunhme.c
> @@ -2863,8 +2863,10 @@ static int happy_meal_pci_probe(struct pci_dev *pdev,
>   			if (!qp->happy_meals[qfe_slot])
>   				break;
>   
> -		if (qfe_slot == 4)
> +		if (qfe_slot == 4) {
> +			err = -ENOMEM;
>   			goto err_out;
> +		}
>   	}
>   
>   	dev = devm_alloc_etherdev(&pdev->dev, sizeof(struct happy_meal));

That's of course simpler, but this also does some cleanup to make it more
obvious what's going on.

> Also, I am curious why happy_meal_pci_probe() doesn't just return instaed
> of branching to err_out. As err_out only returns err.  I guess there is a
> reason for it. But simply returning would probably simplify error handling.
> (I'm not suggesting that approach for this fix.)

I think it's because there used to be cleanup in err_out. But you're right,
we can just return directly and avoid a goto.

--Sean

>> Reported-by: kernel test robot <lkp@intel.com>
>> Reported-by: Dan Carpenter <error27@gmail.com>
>> Signed-off-by: Sean Anderson <seanga2@gmail.com>
>> ---
>>
>>   drivers/net/ethernet/sun/sunhme.c | 7 ++++---
>>   1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/sun/sunhme.c b/drivers/net/ethernet/sun/sunhme.c
>> index 1c16548415cd..523e26653ec8 100644
>> --- a/drivers/net/ethernet/sun/sunhme.c
>> +++ b/drivers/net/ethernet/sun/sunhme.c
>> @@ -2861,12 +2861,13 @@ static int happy_meal_pci_probe(struct pci_dev *pdev,
>>   
>>   		for (qfe_slot = 0; qfe_slot < 4; qfe_slot++)
>>   			if (!qp->happy_meals[qfe_slot])
>> -				break;
>> +				goto found_slot;
>>   
>> -		if (qfe_slot == 4)
>> -			goto err_out;
>> +		err = -ENODEV;
>> +		goto err_out;
>>   	}
>>   
>> +found_slot:
>>   	dev = devm_alloc_etherdev(&pdev->dev, sizeof(struct happy_meal));
>>   	if (!dev) {
>>   		err = -ENOMEM;
>> -- 
>> 2.37.1
>>

Re: [PATCH net] net: sunhme: Return an error when we are out of slots

[Simon Horman]

On Wed, Feb 22, 2023 at 04:07:15PM -0500, Sean Anderson wrote:
> On 2/22/23 15:59, Simon Horman wrote:
> > On Wed, Feb 22, 2023 at 12:09:35PM -0500, Sean Anderson wrote:
> > > We only allocate enough space for four devices when the parent is a QFE. If
> > > we couldn't find a spot (because five devices were created for whatever
> > > reason), we would not return an error from probe(). Return ENODEV, which
> > > was what we did before.
> > > 
> > > Fixes: 96c6e9faecf1 ("sunhme: forward the error code from pci_enable_device()")
> > 
> > I think the hash for that commit is acb3f35f920b.
> 
> Ah, sorry that's my local copy. The upstream commit is as you noted.
> 
> > 
> > However, I also think this problem was introduced by the first hunk of
> > 5b3dc6dda6b1 ("sunhme: Regularize probe errors").
> > 
> > Which is:
> > 
> > --- a/drivers/net/ethernet/sun/sunhme.c
> > +++ b/drivers/net/ethernet/sun/sunhme.c
> > @@ -2945,7 +2945,6 @@ static int happy_meal_pci_probe(struct pci_dev *pdev,
> >   	if (err)
> >   		goto err_out;
> >   	pci_set_master(pdev);
> > -	err = -ENODEV;
> >   	if (!strcmp(prom_name, "SUNW,qfe") || !strcmp(prom_name, "qfe")) {
> >   		qp = quattro_pci_find(pdev);
> > 
> 
> Yes. That's the one I should have blamed.
> 
> > Which leads me to wonder if simpler fixes would be either:
> > 
> > 1) Reverting the hunk above
> > 2) Or, more in keeping with the rest of that patch,
> >     explicitly setting err before branching to err_out,
> >     as you your patch does, but without other logic changes.
> 
> >     Something like this (*compile tested only!*:
> > 
> > diff --git a/drivers/net/ethernet/sun/sunhme.c b/drivers/net/ethernet/sun/sunhme.c
> > index 1c16548415cd..2409e7d6c29e 100644
> > --- a/drivers/net/ethernet/sun/sunhme.c
> > +++ b/drivers/net/ethernet/sun/sunhme.c
> > @@ -2863,8 +2863,10 @@ static int happy_meal_pci_probe(struct pci_dev *pdev,
> >   			if (!qp->happy_meals[qfe_slot])
> >   				break;
> > -		if (qfe_slot == 4)
> > +		if (qfe_slot == 4) {
> > +			err = -ENOMEM;
> >   			goto err_out;
> > +		}
> >   	}
> >   	dev = devm_alloc_etherdev(&pdev->dev, sizeof(struct happy_meal));
> 
> That's of course simpler, but this also does some cleanup to make it more
> obvious what's going on.

Sure. I do think there is merit in a minimal change as a fix.
But I don't feel strongly about it.

> > Also, I am curious why happy_meal_pci_probe() doesn't just return instaed
> > of branching to err_out. As err_out only returns err.  I guess there is a
> > reason for it. But simply returning would probably simplify error handling.
> > (I'm not suggesting that approach for this fix.)
> 
> I think it's because there used to be cleanup in err_out. But you're right,
> we can just return directly and avoid a goto.

Makes sense, thanks.

> --Sean
> 
> > > Reported-by: kernel test robot <lkp@intel.com>
> > > Reported-by: Dan Carpenter <error27@gmail.com>
> > > Signed-off-by: Sean Anderson <seanga2@gmail.com>
> > > ---
> > > 
> > >   drivers/net/ethernet/sun/sunhme.c | 7 ++++---
> > >   1 file changed, 4 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/drivers/net/ethernet/sun/sunhme.c b/drivers/net/ethernet/sun/sunhme.c
> > > index 1c16548415cd..523e26653ec8 100644
> > > --- a/drivers/net/ethernet/sun/sunhme.c
> > > +++ b/drivers/net/ethernet/sun/sunhme.c
> > > @@ -2861,12 +2861,13 @@ static int happy_meal_pci_probe(struct pci_dev *pdev,
> > >   		for (qfe_slot = 0; qfe_slot < 4; qfe_slot++)
> > >   			if (!qp->happy_meals[qfe_slot])
> > > -				break;
> > > +				goto found_slot;
> > > -		if (qfe_slot == 4)
> > > -			goto err_out;
> > > +		err = -ENODEV;
> > > +		goto err_out;
> > >   	}
> > > +found_slot:
> > >   	dev = devm_alloc_etherdev(&pdev->dev, sizeof(struct happy_meal));
> > >   	if (!dev) {
> > >   		err = -ENOMEM;
> > > -- 
> > > 2.37.1
> > > 
>