[PATCH] igb: fix misinterpreted return value of pci_enable_msix

[PATCH] igb: fix misinterpreted return value of pci_enable_msix

[Stefan Assmann]

From: Stefan Assmann <sassmann@redhat.com>

In the igb driver a return value of 0 of function pci_enable_msix is
interpreted as an error case. The correct behaviour is to check < 0 for error
values.

Signed-off-by: Stefan Assmann <sassmann@redhat.com>
---
 drivers/net/igb/igb_main.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
index bb1a6ee..745481d 100644
--- a/drivers/net/igb/igb_main.c
+++ b/drivers/net/igb/igb_main.c
@@ -694,7 +694,7 @@ static void igb_set_interrupt_capability(struct igb_adapter *adapter)
 	err = pci_enable_msix(adapter->pdev,
 			      adapter->msix_entries,
 			      numvecs);
-	if (err == 0)
+	if (err < 0)
 		goto out;

 	igb_reset_interrupt_capability(adapter);
-- 
1.6.5.2

Re: [PATCH] igb: fix misinterpreted return value of pci_enable_msix

[Florian Westphal]

Stefan Assmann <sassmann@redhat.com> wrote:
> From: Stefan Assmann <sassmann@redhat.com>
> 
> In the igb driver a return value of 0 of function pci_enable_msix is
> interpreted as an error case. The correct behaviour is to check < 0 for error
> values.
> 
> Signed-off-by: Stefan Assmann <sassmann@redhat.com>
> ---
>  drivers/net/igb/igb_main.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
> index bb1a6ee..745481d 100644
> --- a/drivers/net/igb/igb_main.c
> +++ b/drivers/net/igb/igb_main.c
> @@ -694,7 +694,7 @@ static void igb_set_interrupt_capability(struct igb_adapter *adapter)
>  	err = pci_enable_msix(adapter->pdev,
>  			      adapter->msix_entries,
>  			      numvecs);
> -	if (err == 0)
> +	if (err < 0)
>  		goto out;
>

The existing code looks correct to me:

      if (err == 0)
            goto out;

      igb_reset_interrupt_capability(adapter);

      /* If we can't do MSI-X, try MSI * */
msi_only:


so the "goto out" appears to be the "success" case.

Re: [PATCH] igb: fix misinterpreted return value of pci_enable_msix

[Stefan Assmann]

On 24.11.2009 11:40, Florian Westphal wrote:
> Stefan Assmann <sassmann@redhat.com> wrote:
>> From: Stefan Assmann <sassmann@redhat.com>
>>
>> In the igb driver a return value of 0 of function pci_enable_msix is
>> interpreted as an error case. The correct behaviour is to check < 0 for error
>> values.
>>
>> Signed-off-by: Stefan Assmann <sassmann@redhat.com>
>> ---
>>  drivers/net/igb/igb_main.c |    2 +-
>>  1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
>> index bb1a6ee..745481d 100644
>> --- a/drivers/net/igb/igb_main.c
>> +++ b/drivers/net/igb/igb_main.c
>> @@ -694,7 +694,7 @@ static void igb_set_interrupt_capability(struct igb_adapter *adapter)
>>  	err = pci_enable_msix(adapter->pdev,
>>  			      adapter->msix_entries,
>>  			      numvecs);
>> -	if (err == 0)
>> +	if (err < 0)
>>  		goto out;
>>
> 
> The existing code looks correct to me:
> 
>       if (err == 0)
>             goto out;
> 
>       igb_reset_interrupt_capability(adapter);
> 
>       /* If we can't do MSI-X, try MSI * */
> msi_only:
> 
> 
> so the "goto out" appears to be the "success" case.

Hi Florian,

thanks for pointing this out. I've jumped to conclusions too fast.
There's a problem with igb MSI-X in RHEL5 in the kdump case and this
fixed it for me. But you're right, it's not the proper solution. I'll
report back when I have more information.

  Stefan

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