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Date: Tue, 8 Jun 2010 14:35:14 -0700
From: Jesse Barnes <jbarnes@virtuousgeek.org>
To: Frank Pan <frankpzh@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
       Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>,
       Yu Zhao <yu.zhao@intel.com>, Chris Wright <chrisw@sous-sol.org>,
       Mitch Williams <mitch.a.williams@intel.com>,
       "Rafael J. Wysocki" <rjw@sisk.pl>,
       "David S. Miller" <davem@davemloft.net>,
       Matt Carlson <mcarlson@broadcom.com>, linux-pci@vger.kernel.org,
       linux-kernel@vger.kernel.org
Subject: Re: Add a helper function in PCI IOV to get VF device
Message-ID: <20100608143514.740f8095@virtuousgeek.org>
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On Tue, 1 Jun 2010 13:05:25 +0800
Frank Pan <frankpzh@gmail.com> wrote:

> Greetings,
> 
> The motivation is make VF device visible to PF driver. PF driver
> may need this to access VF's PCI configuration.
> Another use case is in sysfs symbolic linking. Some of VF's sysfs
> entries are created by PF driver. For example, /sys/class/net/ethx/vfx
> in Intel 82576 NIC driver. Makeing a symbolic link from VF's pci device
> to this path also must be done in PF's driver.
> 
> Currently, there is no hint about VF's bus/devfn in PF's pci_dev.
> The offset and stride entries(which are used to calculate bus/devfn
> of VF devices) in VF's PCI configuration is also invisible in PF's
> driver. So IMO this helper function is needed.
> 
> Any reply is appreciated, THX.
> 
> (ps: gmail will do line wrap/tab replace, use attachment instead to patch)

Per the discussion in this thread it sounds like this really has
nothing to do with sysfs and more to do with being a convenient API for
drivers.

Is that correct?  If so, and assuming there's not some other way of
getting this info from a driver, I'm ok with it, but it should be
submitted as part of a patchset including driver code that uses it.

-- 
Jesse Barnes, Intel Open Source Technology Center
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