[RFC,v2,2/6] net: Add netif_num_vf function

From: Williams, Mitch A <mitch.a.williams@intel.com>

Add a convenience function to determine how many VF devices are associated
with a given PF network interface. If the device is not an SR-IOV physical
function device, the function returns 0.

Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
---

 include/linux/netdevice.h |   27 +++++++++++++++++++++++++++
 1 files changed, 27 insertions(+), 0 deletions(-)


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On Thu, 2009-12-17 at 17:34 -0800, Jeff Kirsher wrote:
> From: Williams, Mitch A <mitch.a.williams@intel.com>
> 
> Add a convenience function to determine how many VF devices are associated
> with a given PF network interface. If the device is not an SR-IOV physical
> function device, the function returns 0.
[...]
> +/**
> + *	netif_num_vf - return number of SR-IOV VFs
> + *	@dev: network device
> + *
> + *	Return the number of SR-IOV virtual function devices that are
> + *	associated with this physical function device. Returns 0 if
> + *	device is not a PF device, or if SR-IOV not enabled.
> + */
> +static inline int netif_num_vf(const struct net_device *dev)
> +{
> +	struct pci_dev *pdev;
> +	int retval = 0;
> +
> +	if (!dev)
> +		goto out;

Why should this function allow dev == NULL?

> +	if (!dev->dev.parent)
> +		goto out;
> +
> +	if (dev->dev.parent->bus == &pci_bus_type) {
> +		pdev = to_pci_dev(dev->dev.parent);
> +		retval = pci_num_vf(pdev);
> +	}
> +out:
> +	return retval;
[...]

It would be much clearer to write:

	struct pci_dev *pdev;

	if (dev && dev->dev.parent &&
	    dev->dev.parent->bus == &pci_bus_type) {
		pdev = to_pci_dev(dev->dev.parent);
		return pci_num_vf(pdev);
	} else {
		return 0;
	}

Ben.

Well, first of all this won't build without CONFIG_PCI
defined.

Second of all, we're not putting PCI crap into netdevice.h

Create a generic device layer abstraction by which you can
fetch these values.

Thanks.
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>Subject: Re: [RFC PATCH v2 2/6] net: Add netif_num_vf function
>
>
>Well, first of all this won't build without CONFIG_PCI
>defined.
>
>Second of all, we're not putting PCI crap into netdevice.h
>
>Create a generic device layer abstraction by which you can
>fetch these values.
>
>Thanks.

OK, I'll respin this and resubmit after the new year.

-Mitch
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