Re: [PATCH 2/2 V3] PCI: implement VFs assignment reference counter

Ethan Zhao
2014-07-11T12:51:36Z

On Fri, Jul 11, 2014 at 8:42 PM, Varka Bhadram <varkabhadram@gmail.com> wrote:
> On 07/11/2014 06:00 PM, Ethan Zhao wrote:
>>
>> Current implementation of helper function pci_vfs_assigned() is a
>> little complex, to get sum of VFs that assigned to VM, access low
>> level configuration space register and then loop in traversing
>> device tree.
>
>
> (...)
>
>
>> @@ -650,6 +630,11 @@ EXPORT_SYMBOL_GPL(pci_vfs_assigned);
>> void pci_iov_assign_device(struct pci_dev *pdev)
>> {
>> pdev->dev_flags |= PCI_DEV_FLAGS_ASSIGNED;
>> + if (pdev->is_virtfn && !pdev->is_physfn)
>> + if (pdev->physfn)
>> + if (pdev->physfn->sriov)
>
>
> Why don't we make last two 'if' conditions into single 'if'
>
> if (pdev->physfn && pdev->physfn->sriov)

Yeah， this one looks better, that style used to tell myself, I might
forget the which side of && operator first, if you sure left first,
I prefer that too :>
>
>
>> + atomic_inc(&pdev->physfn->sriov->
>> + VFs_assigned_cnt);
>> }
>> EXPORT_SYMBOL_GPL(pci_iov_assign_device);
>> @@ -660,6 +645,11 @@ EXPORT_SYMBOL_GPL(pci_iov_assign_device);
>> void pci_iov_deassign_device(struct pci_dev *pdev)
>> {
>> pdev->dev_flags &= ~PCI_DEV_FLAGS_ASSIGNED;
>> + if (pdev->is_virtfn && !pdev->is_physfn)
>> + if (pdev->physfn)
>> + if (pdev->physfn->sriov)
>
>
> same...
same as above.

Thanks,
Ethan
>
>
>> + atomic_dec(&pdev->physfn->sriov->
>> + VFs_assigned_cnt);
>> }
>> EXPORT_SYMBOL_GPL(pci_iov_deassign_device);
>> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
>> index 6bd0822..d17bda2 100644
>> --- a/drivers/pci/pci.h
>> +++ b/drivers/pci/pci.h
>> @@ -235,6 +235,7 @@ struct pci_sriov {
>> u32 pgsz; /* page size for BAR alignment */
>> u8 link; /* Function Dependency Link */
>> u16 driver_max_VFs; /* max num VFs driver supports */
>> + atomic_t VFs_assigned_cnt; /* counter of VFs assigned to VM */
>> struct pci_dev *dev; /* lowest numbered PF */
>> struct pci_dev *self; /* this PF */
>> struct mutex lock; /* lock for VF bus */
>
>
> --
> Regards,
> Varka Bhadram.
>

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