[PATCH 1/2] pci: Error disabling SR-IOV if in VFs assigned

[keith.busch@intel.com (Keith Busch)]

On Mon, Jun 13, 2016@04:14:11PM -0500, Bjorn Helgaas wrote:
> On Tue, May 17, 2016@03:39:58PM -0600, Keith Busch wrote:
> > Every sriov capable driver has to check if any guest is using a virtual
> > function prior to disabling, so let's make it common code.
> > 
> > Signed-off-by: Keith Busch <keith.busch at intel.com>
> 
> If I understand the discussion correctly, this is still racy but
> nobody objects to adding this until we have a better, non-racy
> solution.

My understanding as well: there's a potential race, but no different
than what exists with today.
 
> However, you added this in common code and took advantage of it in
> nvme.  Good so far.  But we have about a dozen other drivers that call
> pci_vfs_assigned().  I assume some of those places could be changed so
> they take advantage of this check in the core instead?

> Can we do that at the same time?  If we add good new stuff and only
> use it one place, there's not as much overall goodness as there would
> be if we updated everybody to do it similarly.

Sounds good, I'll send a series taking advantage of this for all the
other PF drivers duplicating this check in their sriov_configure.