diff mbox series

[V2,2/4] vDPA/ifcvf: implement device MSIX vector allocator

Message ID 20220125091744.115996-3-lingshan.zhu@intel.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series vDPA/ifcvf: implement shared IRQ feature | expand

Checks

Context Check Description
netdev/tree_selection success Not a local patch

Commit Message

Zhu, Lingshan Jan. 25, 2022, 9:17 a.m. UTC
This commit implements a MSIX vector allocation helper
for vqs and config interrupts.

Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
---
 drivers/vdpa/ifcvf/ifcvf_main.c | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

Comments

Michael S. Tsirkin Jan. 25, 2022, 7:36 p.m. UTC | #1
On Tue, Jan 25, 2022 at 05:17:42PM +0800, Zhu Lingshan wrote:
> This commit implements a MSIX vector allocation helper
> for vqs and config interrupts.
> 
> Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
> ---
>  drivers/vdpa/ifcvf/ifcvf_main.c | 30 ++++++++++++++++++++++++++++--
>  1 file changed, 28 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
> index d1a6b5ab543c..7e2af2d2aaf5 100644
> --- a/drivers/vdpa/ifcvf/ifcvf_main.c
> +++ b/drivers/vdpa/ifcvf/ifcvf_main.c
> @@ -58,14 +58,40 @@ static void ifcvf_free_irq(struct ifcvf_adapter *adapter, int queues)
>  	ifcvf_free_irq_vectors(pdev);
>  }
>  
> +static int ifcvf_alloc_vectors(struct ifcvf_adapter *adapter)


So the helper returns an int...

> +{
> +	struct pci_dev *pdev = adapter->pdev;
> +	struct ifcvf_hw *vf = &adapter->vf;
> +	u16 max_intr, ret;
> +
> +	/* all queues and config interrupt  */
> +	max_intr = vf->nr_vring + 1;
> +	ret = pci_alloc_irq_vectors(pdev, 1, max_intr, PCI_IRQ_MSIX | PCI_IRQ_AFFINITY);
> +
> +	if (ret < 0) {
> +		IFCVF_ERR(pdev, "Failed to alloc IRQ vectors\n");
> +		return ret;


which is negative on error...

> +	}
> +
> +	if (ret < max_intr)
> +		IFCVF_INFO(pdev,
> +			   "Requested %u vectors, however only %u allocated, lower performance\n",
> +			   max_intr, ret);
> +
> +	return ret;
> +}
> +
>  static int ifcvf_request_irq(struct ifcvf_adapter *adapter)
>  {
>  	struct pci_dev *pdev = adapter->pdev;
>  	struct ifcvf_hw *vf = &adapter->vf;
>  	int vector, i, ret, irq;
> -	u16 max_intr;
> +	u16 nvectors, max_intr;
> +
> +	nvectors = ifcvf_alloc_vectors(adapter);

which you proceed to stash into an unsigned int ...

> +	if (!(nvectors > 0))

and then compare to zero ...

> +		return nvectors;
>

correct error handling is unlikely as a result.

  
> -	/* all queues and config interrupt  */
>  	max_intr = vf->nr_vring + 1;
>  
>  	ret = pci_alloc_irq_vectors(pdev, max_intr,


As long as you are introducing a helper, document it's return
type and behaviour and then use correctly.

> -- 
> 2.27.0
Zhu, Lingshan Jan. 26, 2022, 12:18 p.m. UTC | #2
On 1/26/2022 3:36 AM, Michael S. Tsirkin wrote:
> On Tue, Jan 25, 2022 at 05:17:42PM +0800, Zhu Lingshan wrote:
>> This commit implements a MSIX vector allocation helper
>> for vqs and config interrupts.
>>
>> Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
>> ---
>>   drivers/vdpa/ifcvf/ifcvf_main.c | 30 ++++++++++++++++++++++++++++--
>>   1 file changed, 28 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
>> index d1a6b5ab543c..7e2af2d2aaf5 100644
>> --- a/drivers/vdpa/ifcvf/ifcvf_main.c
>> +++ b/drivers/vdpa/ifcvf/ifcvf_main.c
>> @@ -58,14 +58,40 @@ static void ifcvf_free_irq(struct ifcvf_adapter *adapter, int queues)
>>   	ifcvf_free_irq_vectors(pdev);
>>   }
>>   
>> +static int ifcvf_alloc_vectors(struct ifcvf_adapter *adapter)
>
> So the helper returns an int...
can fix in V3, thanks for your help!
>
>> +{
>> +	struct pci_dev *pdev = adapter->pdev;
>> +	struct ifcvf_hw *vf = &adapter->vf;
>> +	u16 max_intr, ret;
>> +
>> +	/* all queues and config interrupt  */
>> +	max_intr = vf->nr_vring + 1;
>> +	ret = pci_alloc_irq_vectors(pdev, 1, max_intr, PCI_IRQ_MSIX | PCI_IRQ_AFFINITY);
>> +
>> +	if (ret < 0) {
>> +		IFCVF_ERR(pdev, "Failed to alloc IRQ vectors\n");
>> +		return ret;
>
> which is negative on error...
>
>> +	}
>> +
>> +	if (ret < max_intr)
>> +		IFCVF_INFO(pdev,
>> +			   "Requested %u vectors, however only %u allocated, lower performance\n",
>> +			   max_intr, ret);
>> +
>> +	return ret;
>> +}
>> +
>>   static int ifcvf_request_irq(struct ifcvf_adapter *adapter)
>>   {
>>   	struct pci_dev *pdev = adapter->pdev;
>>   	struct ifcvf_hw *vf = &adapter->vf;
>>   	int vector, i, ret, irq;
>> -	u16 max_intr;
>> +	u16 nvectors, max_intr;
>> +
>> +	nvectors = ifcvf_alloc_vectors(adapter);
> which you proceed to stash into an unsigned int ...
>
>> +	if (!(nvectors > 0))
> and then compare to zero ...
>
>> +		return nvectors;
>>
> correct error handling is unlikely as a result.
>
>    
>> -	/* all queues and config interrupt  */
>>   	max_intr = vf->nr_vring + 1;
>>   
>>   	ret = pci_alloc_irq_vectors(pdev, max_intr,
>
> As long as you are introducing a helper, document it's return
> type and behaviour and then use correctly.
>
>> -- 
>> 2.27.0
diff mbox series

Patch

diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
index d1a6b5ab543c..7e2af2d2aaf5 100644
--- a/drivers/vdpa/ifcvf/ifcvf_main.c
+++ b/drivers/vdpa/ifcvf/ifcvf_main.c
@@ -58,14 +58,40 @@  static void ifcvf_free_irq(struct ifcvf_adapter *adapter, int queues)
 	ifcvf_free_irq_vectors(pdev);
 }
 
+static int ifcvf_alloc_vectors(struct ifcvf_adapter *adapter)
+{
+	struct pci_dev *pdev = adapter->pdev;
+	struct ifcvf_hw *vf = &adapter->vf;
+	u16 max_intr, ret;
+
+	/* all queues and config interrupt  */
+	max_intr = vf->nr_vring + 1;
+	ret = pci_alloc_irq_vectors(pdev, 1, max_intr, PCI_IRQ_MSIX | PCI_IRQ_AFFINITY);
+
+	if (ret < 0) {
+		IFCVF_ERR(pdev, "Failed to alloc IRQ vectors\n");
+		return ret;
+	}
+
+	if (ret < max_intr)
+		IFCVF_INFO(pdev,
+			   "Requested %u vectors, however only %u allocated, lower performance\n",
+			   max_intr, ret);
+
+	return ret;
+}
+
 static int ifcvf_request_irq(struct ifcvf_adapter *adapter)
 {
 	struct pci_dev *pdev = adapter->pdev;
 	struct ifcvf_hw *vf = &adapter->vf;
 	int vector, i, ret, irq;
-	u16 max_intr;
+	u16 nvectors, max_intr;
+
+	nvectors = ifcvf_alloc_vectors(adapter);
+	if (!(nvectors > 0))
+		return nvectors;
 
-	/* all queues and config interrupt  */
 	max_intr = vf->nr_vring + 1;
 
 	ret = pci_alloc_irq_vectors(pdev, max_intr,