Re: [PATCH] portdrv: Use pci_enable_msix_range() instead of pci_enable_msix()

[Alexander Gordeev <agordeev@redhat.com>]

On Wed, Feb 19, 2014 at 03:09:41PM -0700, Bjorn Helgaas wrote:
> On Wed, Feb 19, 2014 at 3:15 AM, Alexander Gordeev <agordeev@redhat.com> wrote:
> > As result of deprecation of MSI-X/MSI enablement functions
> > pci_enable_msix() and pci_enable_msi_block() all drivers
> > using these two interfaces need to be updated to use the
> > new pci_enable_msi_range() and pci_enable_msix_range()
> > interfaces.
> >
> > Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
> > Cc: Bjorn Helgaas <bhelgaas@google.com>
> > Cc: linux-pci@vger.kernel.org
> > ---
> >  drivers/pci/pcie/portdrv_core.c |   17 ++++++++++-------
> >  1 files changed, 10 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
> > index 986f8ea..4e46eca 100644
> > --- a/drivers/pci/pcie/portdrv_core.c
> > +++ b/drivers/pci/pcie/portdrv_core.c
> > @@ -99,8 +99,9 @@ static int pcie_port_enable_msix(struct pci_dev *dev, int *vectors, int mask)
> >         for (i = 0; i < nr_entries; i++)
> >                 msix_entries[i].entry = i;
> >
> > -       status = pci_enable_msix(dev, msix_entries, nr_entries);
> > -       if (status)
> > +       status = pci_enable_msix_range(dev,
> > +                                      msix_entries, nr_entries, nr_entries);
> 
> This is a place we could use pci_enable_msix_exact(), isn't it?  (Also below.)

Yes, absolutely.

I posted it (and other updates) as is, since I understood
pci_enable_msix_exact() is not going to make it into 3.14. Was I wrong here?

I think more time in testing with either pci_enable_msix_range() or
pci_enable_msix_exact() is good. And a follow-up switch from
pci_enable_msix_range() to pci_enable_msix_exact() should be easy eigher.

What do you think is the best course of action now? 

> > +       if (status < 0)
> >                 goto Exit;
> >
> >         for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++)
> > @@ -159,21 +160,23 @@ static int pcie_port_enable_msix(struct pci_dev *dev, int *vectors, int mask)
> >                 idx[PCIE_PORT_SERVICE_AER_SHIFT] = i;
> >         }
> >
> > +       status = 0;
> > +
> >         /*
> >          * If nvec is equal to the allocated number of entries, we can just use
> >          * what we have.  Otherwise, the port has some extra entries not for the
> >          * services we know and we need to work around that.
> >          */
> > -       if (nvec == nr_entries) {
> > -               status = 0;
> > -       } else {
> > +       if (nvec != nr_entries) {
> >                 /* Drop the temporary MSI-X setup */
> >                 pci_disable_msix(dev);
> >
> >                 /* Now allocate the MSI-X vectors for real */
> > -               status = pci_enable_msix(dev, msix_entries, nvec);
> > -               if (status)
> > +               nvec = pci_enable_msix_range(dev, msix_entries, nvec, nvec);
> > +               if (nvec < 0) {
> > +                       status = nvec;
> >                         goto Exit;
> > +               }
> >         }
> >
> >         for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++)
> > --
> > 1.7.7.6
> >
> --
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-- 
Regards,
Alexander Gordeev
agordeev@redhat.com